BNSF AC4400CW

[M636C]

Ulrich (and Mark)

Firstly, I didn't know that BNSF were buying AC4400CWs, could you say how many, and when they'll be delivered?

But, as you say, they bought three, presumably for testing, some time ago.

If you look at the technical features of the locomotives, SD70MAC and AC4400CW, what are the differences? Firstly, the AC4400CW is more powerful, with a horsepower up by ten percent. It has a different system of AC inversion. The GE locomotives have a separate inverter for each axle, while the EMD units use two inverters, one for each truck. This can't be a big problem, since BNSF own most of the SD70MACs.

If the order has just been placed, what other reasons could there be? Perhaps BNSF were offered the SD70ACe by EMD, and decided that these did not have as much in common with their existing SD70MAC fleet, and perhaps would be more susceptible to failure while the design was new and early problems were sorted out. So possibly, the option of "Buying more of the same" wasn't there any more. Perhaps EMD didn't want to build any more old type SD70MAC locomotives.

There is a lot in common between the Dash9-44CW and the AC4400CW, apart from the actual electrical equipment. The reason the Dash9-44CW has a smaller air intake than the Dash 8 is because that part of the unit is the same as the AC4400CW. If a maintenance fitter is familiar with the Dash 9, he'll be able to understand the AC 4400 as long as he has been instructed on the new equipment, and remembers that the heavy electrical switchgear and the air conditioner have exchanged places.

GE could build the locomotives fairly easily: just take a UP AC4400CW and put a BNSF gull wing cab on it. It is possible that GE could deliver earlier, and if the comments on other threads are true, the GE might have been cheaper.

Another point is that GE are introducing a new locomotive, which I've seen described as an EV45CTE. Suppose EMD couldn't deliver until tier II emissions compliance was compulsory (thus giving a locomotive that was quite different), but GE could deliver a locomotive very similar to the existing Dash 9 now, but if you wait you will have to take their tier II locomotive with a new 12 cylinder engine.

If that scenario applied BNSF would take the simplest option and buy the AC4400CW! Remember that he first SD70MAC was delivered more than ten years ago. It would not be possible today to buy the electronic components used in that locomotive, even if you wanted to.

It seems to me that BNSF might have taken the easy option, not the hard one!

Peter

[Anonymous]

[#ditto][#ditto][#ditto][#ditto][#ditto]

EMD rules!

[Anonymous]

[%-)][bow][%-)]

Why buyed the BNSF now some GE AC4400CW´s?

Okay, they buyed three for testing some years ago, but this is no reason.

Why not some more SD70MAC? This model is also available, they own a huge fleet and maintenance is cheaper with not so much types in use?

Nobody tells or wrote the "Why"!

Because this are CTE´s and this function isn´t available from EMD?
Because the BNSF need some AC´s more and EMD could not deliver in a good time?

I find no logic in this doing - I think the Dash 9 is the "normal" BNSF engine and the SD70MAC is the "heavyduty AC".